The present invention relates to implants.
In particular, the present invention relates to implants which have an elongated configuration and which are intended to be introduced into a tubular body organ.
As is well known, when an implant of this type is introduced into a tubular body organ, it is important to fix the implant in the tubular body organ. For this purpose such implants have been provided at their exterior with a tissue-ingrowth structure in the form of a porous matrix having pores into which the tissue will grow in order to provide a secure positioning of the implant in the body organ. In addition, this secure positioning is of particular importance in connection with implants such as vas valves which are received in a vas deferens because the engagement of the exterior of the valve with the tissue of the vas deferens will reliably prevent sperm from travelling along the exterior of the valve, thus bypassing the latter and defeating the purpose of the valve. Thus in general it is important to fixedly determine the location of the implant in the tubular organ and in certain specific cases such as the case of the vas valve, other important objectives are to be achieved by the growth of tissue into the pores of the ingrowth structure.
During the time interval immediately subsequent to introduction of the implant, the tissue has not yet grown into the ingrowth structure, so that it becomes necessary to provide the best possible conditions for tissue ingrowth while maintaining the implant in the desired position through means other than the ingrowth of tissue. For the purpose it has been customary to use sutures, but the application of sutures by a surgeon has proved to be extremely inconvenient and furthermore does not achieve the desired results in the best possible manner. Thus, even if sutures are used for temporarily holding the implant in position in the interior of the tubular body organ, it is still possible for the tubular body organ to move with respect to the implant. Thus even if sutures are capable of preventing, at least to some extent, longitudinal movement of the tubular body organ and the implant one with respect to the other, such sutures cannot prevent circumferential or twisting movement of the tubular body organ and the implant one with respect to the other. Any movment of this type, whether longitudinal or circumferential twisting, between the implant and the tubular body organ, retards the growth of tissue since the tissue will grow into the ingrowth structure in an ideal manner only when the tissue which engages the ingrowth structure is immobilized with respect thereto.